Reader x Undertale!
by Anime Splatter
Summary: So yeah, you basically have relations with each and every Undertale character. Let me know which character you wanna smash first. Rated M for further chapters ;) Who do you want? Every character in Undertale, of course, except Temmie (- -)
1. Chapter 1

**Howdy! If you couldn't tell. This is a romance story. #dealwithit.**

You wake up with a jolt. After a terrible nightmare of scary dragons and talking flowers, you decide to head out to explore the construction of the new monster school. You put on your favorite blue and purple striped T-shirt, and head out. You look out at the construction zone to see Toriel, wearing a hard hat and a construction uniform.

"Oh, good morning my child!" Toriel turns and waves.

"Hi mom. How is the construction going?"

"Oh, it's alright. We have 4 people working on it at this exact moment."

"What about Sans? I only see Papyrus, Asgore, Undyne, and Alphys." Just as you say that, a little skeleton in a blue hoodie begins floating over you, staring.

"Hey buddy. Want a hot dog?" He pulls a hot dog out of nowhere.

"Ugh, no thanks. I'd rather eat Papyrus's frozen spaghetti." As you say that, the tall skeleton begins to walk over to you.

"What's this I hear about my spaghetti?"

"Oh um..." You begin to act a bit scared. "Oh, uh, I-I said, that I'd um, eat your spaghetti?"

"WOWIE! Thanks, human! See Sans? People do in fact like my spaghetti." Papyrus looks upward for that little plump teleporter. "Sans? Where did you go? I was in the middle of a boast." We begin to walk around the school. Sans is able to be seen on the ceiling of the school, sleeping.

"Anyway, mom, I was meaning to ask you where Asriel was." Toriel points to the supposed school yard. You can see a small orange lily in the soil. You begin to walk over to it.

"Hey Asriel."

"What do you want, (y/n)?"

"Nothing, just to relax with you."

"...sure." You lean back and look at the sun and clouds above you.

"I've been meaning to ask you something, (y/n)."

"Yeah?" You turn your head to face Flowey.

"You've broken the barrier, you and every other monster has left the underground. what do you intend to do now?"

"Well," You begin to think. " I just want to spend the rest of my life with you?

"W-With me? But... I... Y-You can reset after dying!" Flowey stutters.

"Well, that's good. I'd love to spend all eternity with one person. And that is you." Flowey blushes intensley.

"Well, you can't."

"What do you mean?" You seem confused and suprised.

"I can just leave, like this." Flowey pops into the earth and re-enters about 2 feet away. Then, he pops back into the earth, and re-appears next to you. "See?"

"I thought you would say something like that, so I brought this." You reach into your pocket and a digital screen pops out in front of you. Flowey stares at the screen and sees what you highlighted. He sighs. You take your hand out your pocket, and reveal a flower pot.

"You really like me that bad? Fine. Let's go."

You reach into the soil, and pull a huge clump out. You fill the pot. Flowey suddenly pops out of the soil.

"Heh. Let's go home." You grin.

"Yeah let's go home. Asriel." Flowey blushes.

Completing a chapter with a new friend FLOWERS YOU WITH DETERMINATION!


	2. The Undying (Austin)

You enter Waterfalls. As expected, an armoured civilian walked around. She takes of her helmet, pushing red hair into your face. She notices, and pulls back immediately.

"Oh! (Y/N)! Sorry! Didn't see ya there. It seems we're the only ones underground..." She walks close to you, making both of you blush.

"Wanna rob every store in Snowdin?" She says, smiling.

"Uh... ok?" You say.

You and Undyne walk throughout the Underground, taking money from places like inns and Grillby's. The coldness of the area made here want to take her armour off.

"Hey... uh, your not to bad. At robbing, I mean." You say to Undyne.

"Oh, shut up! I've done this for years, by myself at least..." She says, blushing.

"Who said you have to do this alone?" You take Undyne's hand in your own. "Adventure with me! Be with me for the rest of our lives!"

"(Y/N)... I can't believe it. I've felt like this too!" Undyne says, jumping into your arms. You push her so that she's close to your face, pushing her pants against the bulge in your pants. Then, you tenderly kiss her, exploring every part of her mouth. She then releases.

"Come here. There's a special place we should go. It's to cold for what I'm going to do to you."

 _What? Yall are enjoying this? Ok Austin. Thanks for the idea. let me know who ya'll wanna smash next. See ya!_


	3. Undyne (austin)

She brings you to the Snowed Inn. As expected, the place was empty. Undyne steals from the cash register and enters one of the rooms. She then beckons you. Entering the room, you slowly take off your shirt. The lights remained on.

"Hmmm..." Undyne licks her lips. "You read my mind."

"Hmpf, you better believe it." You slowly walk over to Undyne, who takes her pants off quickly. She grabs your chest with both hands and places you on the bed. Her panties soak through the bulge in your pants.

"Well, if we want any fun, this's gotta go." Undyne claws at your pants and tears them away from you. Then, she throws it aside. Then, takes your underwear off as you follow. Then, without any warning, rams herself ontop of you. A warm liquid covers your penis, and red pours out of Undyne.

"Mmf... no pain.. no gain.." You chuckle a bit.

"S-something funny?!" Undyne's head turns red.

"It's okay to loosen up on me, okay?" Undyne nods, and changes position. Then, she puts herselfon you again, but even deeper. She goes deeper and deeper, yet suddenly stops and rubs your penis against her vagina's walls. She then again slams herself farther down your length.

"God... why are you so huge?" She then stands up, and her vagina drips. She then moves herself and begins to stroke your cock up and down, then licks your tip. She then puts her whole mouth on you, and begins deep throating you. An erotic moan is made alongside a pop as Undyne releases her mouth. You both were definitely at her edge, as you both came at the same time once she sat on you, filling her to the brim and more. She lays on you as you slowly drift to sleep...

[SAVE LOADED]


	4. Mettaton ( Sebastian )

"Oh hey. Your back quicker than I thought." Flowey says.

" Goddammit, Fuck off, man."

"What? Oh no, I applaud your work. As a matter-of-fact, I'll help." Flowey steals the computer and hacks into the author's account.

"Huh... ok. I'll send you to Alphys' lab."

"Yeah sure. Mind downloading a fouth wall breaker app?"

"Shut up." Flowey returns the computer and 2 vines stick out the ground. They pierce through all the walls, all the way to Hotlands. Once he drops you off, A mechanic voice appears from behind you.

"OOOOHHHHHHH. Good evening darling. Quiet ironic to see you here. I just started a new TV program. It's rated R. It's how to have sex like an actual porn star."

"Oh but of course." You say, neutral. Mettaton turns around, arching his back.

"Would you please?" You realize what he was refering to, and flip his switch. Steam is ejected from the sides of his wheel, as his shadowy figure appears in the midst. He, unlike his usual appearance has on no pants or shirt. You notice the shine off his waist that glows down his penis.

"Now, darling, you should undress too, hmm?" You shake as you take your pants and underwear off with one hand.

"No need to be nervous darling. I'm here too. Absolutely naked on TV." He walks up to you and straddles you.

Licking his lips he says " Now lets get busy." He licks and sucks on your neck, making you shiver in every stroke as it feels like cold and wet iron on your neck.

"Hnnn.."

"C'mon darling, It's your turn." Mettaton sprawls out. You crawl torwards him. You wrap an arm around his penis, and rub it slowly, treating it gently, like fine china. Picking up the pace, you push up and down quickly. Eventually, oil spurts out of his tip, causing him to moan. You rap your mouth around his tip and suck hard, pulling his length down your throat. Later, a warm liquid pours down your throat.

"Oh, darling, that was magnificent. My turn now~" Mettaton quickly rubs your cock, eager to make you cum. Your pulsating cock releases a liquid that shoots on Mettaton's face. He then starts sucking your cock, pulling your whole appendage down his throat, which shoots into his mouth.

"Hmpf. That was interesting. Well, I believe you'll pass out now, so good night." You drift to sleep...

[Save Loaded]


	5. Muffet (Wow, such people)

_Well shit. Alright, here's your... stuff... Imma go chug bleach after this._

You decided to wander through Hotlands next. It was quite hot, and you were a bit tired. Luckily, you came across Muffet's, and then decided to relax there. She added air conditioning and benches to bribe people.

It wasn't working very well.

Muffet lays on her stand, 2 of her arms under her chin. She notices you enter.

"Oh, a customer? Would you like to buy something?"

"Uh, sure. How much for cider?"

"Oh, you can get a sample and try it. It's 80 G."

"80 G? You really improved, huh, Muffet?"

"Yep!" Muffet puts two hands on her hips, and pushes her chest out, proud. You pull out your wallet.

"80 G right? Here you go." You hand over the money. Muffet hands you a jug with delight.

"My first real sale..."

"Why not just make a shop on the surface? The barrier is broken."

"Why are you not asleep yet?" You begin to question Muffet's comment before falling on the ground. It doesn't hurt, the floor is smooth and soft. But you do lose consciousness. You wake up with only underwear on.

Before screaming, you asses the situation. Your nearly naked. Alright, you think. Well, let's- Wait, are those footsteps? Shit, alright. Just breathe.

Muffet enters the room completely naked.

"Okay, before the concrete hardens, can we first make sense of what's happening here?"

"Well, it's obvious," Muffet says, covering her Double D's. I'm gonna fuck you." She moves her arms and walks over to you.

"Am I at least on a bed?"

"Yeah. Aren't you gonna fight back?" Muffet stops.

"Not really, I'll just tire myself out. besides, I'm fine having sex with you." Muffet blushes a deep shade of purple.

"I'll make you swallow those words, (Y/N)." Muffet continues walking.

"I'll make you swallow my dick." The string around you loosens. You pull a hand out and release yourself. The second your released, however, Muffet tackles you.

"Hah, gotcha!" Muffet says, grinning.

"Sure about that?" You quickly clamp onto her tit. She gasps in surprise. As you suck on her nipple, she pulls your head close. You release.

" 'Hah, gotcha!' " You say, in a mimic-ing voice. Her face flushes.

"Well, dearie, guess your ready..." Confusion. Muffet grabs your underwear and pulls them down, surprised by the unnatural "thing" in your pants.

"That's... an unexpected size. I never knew humans could grow that long." Muffet looks away, blushing.

"Hey." Muffet looks torwards you. "Your gonna take in all 8 1/2 inches of it.

"I-" You shove yourself into her. She makes a pace after a while, bobbing her head up and down, eventually moving onto plan... something...

"Well jeez, that mouth can do wonders, huh Muffet?"

"Can yours?" Muffet says, jumping on you. Sitting on your chest, her vagina in your face. All you did was lick repeatedly, Muffet kept your head in the right direction.

A bit after, Muffet releases you, and lays down, her back on the floor. You lay on top of her, and grab your penis.

"Ready for this now?" Muffet nods. She really did do wonders. The shortly after, you feel the tingling. You stare into her eyes, her black sclera and purple pupils, thrust as deep into her as you could, which was pretty far, and you came. You pulled out and sat.

"Well, Muffet. That was amazing. You got a shower here or something?" You say, standing up.

"You're not tired? Oh, and third door to the left." Muffet says panting.

"Yeah, I actually am. But, ya know, I got this and that to do. Don't worry, we'll meet again. Oh, shit, almost forgot. Where are my clothes?"

"In tbe bathroom." Muffet says, climbing on the bed.

"Thanks. Good night." You say, walking off, and closing the door behind you.

 _Happy? Now, before I kill myself, I'd like you to know, that a shit ton of people requested this. If you didn't want to see this, then request what you do want me to write, and I will come back from heaven(or hell, doubt it tho) and write this for you. Welp. FUCK LIFE._


End file.
